Form Transparent

[Sina]

HI
I have a problem :
when I enable form color transparent or alpha blend then at run time when i drag the form the dragging speed is low how can I prevent it?
any idea?
best regards

[Johnny_Bit]

get ussed to it. really, there's no other way... maybe you should check you hardware rather than software

[kokkoras]

It's mainly a matter of how powerfull is your VGA card.

[Sina]

well I've got a 128mb ATI VGA card and I don't think it is weak!
but there's something else is there any api doing transparency?
because I saw other programs using transparency with normal speed !

[kokkoras]

DirectX and/or OpenGL comes in mind. Sorry, can't help nore.

[Johnny_Bit]

atually, there is. alphablend is pretty normal for windows, but to make special points invisible, you have to use some sick windows api, also remember that sometimes making things in pure winapi saves you many moments of "argh, this is so slow", so check msdn and have happy progamming

[kokkoras]

Transparency exists since Win2K. I remember making transparent the windows of some nice tool apps (like the legendary Total Commander) by using some hacks but moving the transparent window around was like a slide show that time. It was quite acceptable though in an nVidia Ti4200 (that I still use BTW).

[Kambiz]

Which level of transparency you need?

If you don't need semi-transparency, you should use Windows regions to improve speed.

By the way, in opposite of alpha belending, all 32 bit version of Windows support regions.

[Sina]

Mr.Kambiz I need to hide one part of my form to make it more stylish I think it means full transparensy level
But I don't want to use win regions because my form doesn't want a simple shape
thanks

[kokkoras]

By the way, I had alpha blending in mind.

[Kambiz]

Mr.Kambiz I need to hide one part of my form to make it more stylish I think it means full transparensy level
But I don't want to use win regions because my form doesn't want a simple shape
thanks

A region can be any complex shape. For example, look at the Office Assistant package, trancparency of each frame is achieved by applying a region. The oaBitmap unit of the package has some routines for creating a region from a bitmap.

[Kambiz]

Here is a sample:

[Sina]

Thank you I'll try it

[Sina]

Mr.Kambiz would you plz release the sample program code {one in your previous post picture}
?
//////////////
Thanx

[Kambiz]

Sorry for being so late. I was not on the forum for a while.

Code: Select all

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    btnClose: TButton;
    Image: TImage;
    procedure FormCreate(Sender: TObject);
    procedure btnCloseClick(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses
  oaBitmap;

procedure TForm1.FormCreate(Sender: TObject);
var
  rgnForm: HRGN;
  rgnTemp: HRGN;
begin
  BorderStyle := bsNone;
  with Image.Picture do
    rgnForm := CreateBitmapRgn(Bitmap, Bitmap.Canvas.Pixels[0,0]);
  rgnTemp := CreateRectRgnIndirect(btnClose.BoundsRect);
  try
    CombineRgn(rgnForm, rgnForm, rgnTemp, RGN_OR);
  finally
    DeleteObject(rgnTemp);
  end;
  SetWindowRgn(Handle, rgnForm, False);
  // Windows owns rgnForm, therefore we might not delete it.
end;

procedure TForm1.btnCloseClick(Sender: TObject);
begin
  Close;
end;

end.